Cardiac valve prosthesis

ABSTRACT

A cardiac valve prosthesis including an armature for anchorage of the valve prosthesis at an implantation site. The armature defining a lumen for the passage of the blood flow and having a longitudinal axis, and a set of prosthetic valve leaflets supported by said armature and configured to move, under the action of blood flow, in a radially divaricated condition to enable the flow of blood through said lumen in a first direction, and in a radially contracted condition, in which said valve leaflets co-operate with one another and block the flow of blood through the prosthesis in the direction opposite said first direction. The armature including an annular part and a pattern of arches struts carried by said annular part, said pattern of arched struts having proximal ends connected to said annular part, and distal ends spaced axially from the proximal ends and opposite said annular part, a plurality of sets of anchoring formations configured to protrude radially outwardly of said annular part, each set being supported by a least one of said annular part and a corresponding arched strut, and a plurality of support posts, each support post being supported by adjacent arched struts, wherein the sets of anchoring formations alternate with the support posts around said longitudinal axis.

FIELD OF THE DISCLOSURE

The present disclosure relates to cardiac valve prosthesis. Morespecifically, the disclosure has been developed with reference toso-called “stented” cardiac valve prostheses, i.e. featuring a supportstructure and a prosthetic heart valve carried by the support structure,wherein the support structure is generally referred to as “armature” andis provided as a stent member.

BACKGROUND

Some cardiac valve prostheses include a multi leaflet prosthetic heartvalve sutured, stitched, or otherwise permanently connected to thearmature, which defines a lumen for the passage of blood through theprosthesis. The armature is provided as a stent member, and as such itexhibits extensive deformation capabilities. Typically, an armature of astented cardiac valve prosthesis features a radially collapsedconfiguration intended for delivery and positioning of the same to andat the implantation site (for example via a delivery instrument such asa catheter), and a radially expanded configuration which is intended toensure that the prosthesis is withheld at the implantation site onceimplanted.

Sometimes, the prosthetic valve includes a set of prosthetic valveleaflets supported by the armature and configured to move, under theaction of blood flow, in a radially divaricated condition to enable theflow of blood through the lumen in a first direction, and in a radiallycontracted condition, in which the valve leaflets co-operate with oneanother (so-called leaflet coaptation) and block the flow of bloodthrough the prosthesis in the direction opposite said first direction.

As the prosthetic valve is coupled to the armature, there is a certaindegree of structural interaction between the same, which results in theoperation of the prosthetic valve being possibly affected by thestructural condition the armature experiences at the end of theimplantation procedure, with the valve sitting at the implantation site.The shape of the implantation site (the valve annulus) may affect the invivo functionality of the valve. For example, a D-shaped annulus mayencourage leaflet straightening, which in turn may end up withnegatively affecting leaflet coaptation. This happens generally becausethe irregular shape of the annulus, meaning by this a deviation from theideal circular shape. As a D-shaped annulus may notionally be regardedas a “flattened” circular annulus, the armature of the prosthesis willexperience an irregular deformation pattern over the perimeter of theannulus, and especially over the “flattened” portion. This may result ina sensible change, for example, in relative position of support posts ofthe armature to which the prosthetic valve is attached, and especiallyan increase in the mutual distance between two supporting posts possiblylocated at the “flattened” side. Such an increase in distance causes theleaflet straightening referred to above, which in turn is susceptible ofencouraging regurgitation of blood through the prosthesis. This isclearly an undesirable condition, in that functionality of the nativeheart valve replaced by the prosthesis will not be restored, not tomention the damage that this could cause to an already sufferingpatient.

Additionally, radially protruding anchoring formations possibly providedon the armature of the prosthesis may affect the resistance to bendingwhen the prosthesis is implanted at sites such as the annulus of abicuspid valve, or a flat Valsalva Sinus. Accordingly, the prosthesiswill be subject to a bending phenomenon known as “folding”, which isanother major source of risks and damage to the patient.

SUMMARY

In a first example, a cardiac valve prosthesis comprising an armaturefor anchorage of the valve prosthesis at an implantation site. Thearmature defining a lumen for the passage of the blood flow and having alongitudinal axis, and a set of prosthetic valve leaflets supported bysaid armature and configured to move, under the action of blood flow, ina radially divaricated condition to enable the flow of blood throughsaid lumen in a first direction, and in a radially contracted condition,in which said valve leaflets co-operate with one another and block theflow of blood through the prosthesis in the direction opposite saidfirst direction. The armature comprising an annular part and a patternof arched struts carried by said annular part, said pattern of archedstruts having proximal ends connected to said annular part, and distalends spaced axially from the proximal ends and opposite said annularpart. Where, a plurality of sets of anchoring formations configured toprotrude radially outwardly of said annular part, each set beingsupported by at least one of said annular part and a correspondingarched strut, and a plurality of support posts, each support post beingsupported by adjacent arched struts. Where, the sets of anchoringformations alternate with the support posts around said longitudinalaxis.

In a second example according to the first example, wherein each set ofanchoring formations extends bridge-wise between a corresponding archedstrut and said annular part.

In a third example according to the first example or the second example,wherein each support post is cantilevered to adjacent arched struts.

In a fourth example according to any of the previous examples, whereineach arched strut extends from a first proximal end, to a distal end,and then to a second proximal end.

In a fifth example according to the fourth example, wherein each set ofanchoring formations extends bridge-wise from an arched strut to aportion of the annular part comprised between two proximal ends.

In a sixth example according to the fifth example, wherein each set ofanchoring formations comprises two anchoring formations.

In a seventh example according to the fifth example or the sixthexample, wherein each anchoring formation comprises a serpentine, aweaving, or an apertured pattern.

In an eighth example according to the fourth example, wherein eachsupport post is angularly arranged between two adjacent arched struts atan inter-strut position, said inter-strut position corresponding to theposition of a proximal end shared between said two adjacent archedstruts.

In a ninth example according to the third example or the eighth example,wherein said support post is cantilevered to said pair of arched strutsby way of a first and a second cantilever struts merging at thesupporting post.

In a tenth example according to any of the previous examples, whereinsaid annular part is covered by a cuff to provide sealing at theimplantation site, the cuff being arranged outside of the lumen of thearmature.

In an eleventh example according to the tenth example, wherein the cuffis separate from said set of prosthetic valve leaflets.

In a twelfth example according to any of the previous examples, whereinsaid annular part includes one or more coupling elements configured tobe engaged by valve loading or crimping facilities or instruments.

In a thirteenth example according to any of the previous examples,wherein said set of prosthetic valve leaflets define a prosthetic aorticvalve, the cardiac valve prosthesis being an aortic valve prosthesis.

In a fourteenth example according to the first example, wherein eacharched strut includes a distal portion at the distal end thereof whichis substantially C-shaped and is configured to mate with a valve holderor a carrier portion of a delivery instrument.

In a fifteenth example according to the first example or the fourteenth,wherein the pattern of arched struts includes inter-strut portionsarranged at said proximal ends, and said annular part has a meshstructures including cells and nodes, said inter strut portions having aY-shape or a U-shape extending through nodes of the mesh of the annularpart.

In a sixteenth example, a cardiac valve prosthesis comprising:

-   -   an armature for the valve prosthesis at an implantation site,    -   a set of prosthetic valve leaflets supported by said armature,    -   the armature comprising:    -   an annular part    -   a plurality of arched struts coupled to said annular part,    -   a plurality of support posts each having a free proximal end and        a distal portion supported by adjacent arched struts.

In a seventeenth example according to the sixteenth example, furtherincluding a plurality of sets of anchoring formations configured toprotrude radially outwardly of said annular part, each set beingsupported by at least one of said annular part and a correspondingarched strut.

In an eighteenth example according to the sixteenth example, the supportposts are cantilevered to adjacent arched struts.

In a nineteenth example according to the seventeenth example, each setof anchoring formations extends bridge-wise between a correspondingarched strut and said annular part.

In a twentieth example according to the seventeenth example the sets ofanchoring formations alternate with the support posts around alongitudinal axis of the prosthesis.

While multiple embodiments are disclosed, still other embodiments of thepresent disclosure will become apparent to those skilled in the art fromthe following detailed description, which shows and describesillustrative embodiments of the disclosure. Accordingly, the drawingsand detailed description are to be regarded as illustrative in natureand not restrictive.

BRIEF DESCRIPTION OF THE FIGURES

Further features and advantages of the disclosure will become apparentfrom the following description with reference to the annexed drawings,given purely by way of non-limiting example, in which:

FIG. 1A is a perspective view of a cardiac valve prosthesis, accordingto embodiments of the disclosure;

FIGS. 1B and 1C illustrate examples of trimmed portions of leafletforming members, according to embodiments of the disclosure;

FIG. 2 is a perspective view of an armature of the prosthesis of FIG. 1, according to embodiments of the disclosure;

FIG. 3 is an orthogonal view of the armature of FIG. 2 according to IIIin FIG. 2 , according to embodiments of the disclosure;

FIG. 4 is another orthogonal view of the armature of FIG. 2 according toIV in FIG. 2 , according to embodiments of the disclosure;

FIG. 5 is a further orthogonal view of the armature of FIG. 2 accordingto V in FIG. 2 , according to embodiments of the disclosure;

FIG. 6 is yet a further orthogonal view of the armature of FIG. 2according to VI in FIG. 2 , according to embodiments of the disclosure;and

FIG. 7 is exemplary of an implantation of the heart valve prosthesis,according to embodiments of the disclosure.

While the disclosure is amenable to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and are described in detail below. Theintention, however, is not to limit the disclosure to the particularembodiments described. On the contrary, the disclosure is intended tocover all modifications, equivalents, and alternatives falling withinthe scope of the disclosure as defined by the appended claims.

DETAILED DESCRIPTION OF EMBODIMENTS

With reference to FIG. 1A, reference number 1 designates as a whole acardiac valve prosthesis according to various embodiments of thedisclosure. The cardiac valve prosthesis 1 includes an armature 2 foranchorage of the valve prosthesis at an implantation site. The armature2 defines a lumen for the passage of the blood flow and has alongitudinal axis X1.

The prosthesis 1 also includes a set of prosthetic valve leaflets 4supported by the armature 2 and configured to move, under the action ofblood flow (which has a main flow direction roughly corresponding tothat of the axis X1): in a radially divaricated condition to enable theflow of blood through the lumen in a first direction, and in a radiallycontracted condition, in which the valve leaflets 4 co-operate with oneanother and block the flow of blood through the prosthesis 1 in thedirection opposite the first direction. This is commonly referred to asleaflet coaptation.

With reference to FIGS. 2-5 , in embodiments the armature 2 includes anannular part 6, and a pattern of arched struts 8 carried by the annularpart 6. The annular part has a structure which can expand from aradially contracted condition, associated to delivery of the prosthesisto implantation site, to a radially expanded condition wherein theprosthesis is withheld at the implantation site. In these embodiments,the annular part may have a mesh structure including an annular patternof multiple strut clusters (cells) having polygonal shape (hexagonal,rhomboidal, etc.).

As regards the construction of the set of leaflets 4 (also referred toas or valve sleeve), in various embodiments the prosthetic valve is madewith three separate leaflets. Each leaflet is obtained from one sheet ofpericardium trimmed accordingly to FIG. 1B, i.e., according to asubstantially lobe-shaped figure. Each trimmed leaflet features twopatterns of sewing holes SH and two side wings SW.

The patterns SH are sewn together forming a sewn stiffer fold whichfollows the leaflet profile at the root thereof, thereby forming thecusp.

The two side wings SW enable connection of the valve to supporting postsin the valve armature. The sewn fold has the purpose to bias the cuspinwardly thereby encouraging leaflet coaptation, and to avoid contactbetween the armature 2 and the valve leaflets 4 avoiding the risk ofabrasion due to repeated impact against the armature 2, which, in someembodiments, is a metal material.

The two patterns of holes SH may be sewn together using a suture threadcoated with a film of biocompatible material or PET thread or PTFEfilament.

The sewing pattern may be varied to accommodate the directionaldifferences in the forces exerted at each point of the stitches, preventthe stitches from triggering fatigue fracture lines.

Preferably the stitching follows the pattern identified by letter “C” inFIG. 1C (alternate inner and outer surface stitches). The three leaflets4 are then joined at the side wings SW and stitched together along theleaflet post line, i.e., at the interface of adjacent side wings SW,thereby forming a conical duct.

The side wings SW, which allow a slack of material that protrudesoutwardly of the duct, are then fixed to the armature posts, which arefully wrapped by the side wings SW.

The extra tissue skirt below the stitching holes SH allows leafletfixation to the inflow ring 6 of the stent, by mean of a stitching line.Additionally, in some embodiments one—preferably the lower one or bothof the patterns SH may be stitched to the armature at the annular part6.

A strip of pericardium is finally stitched to the inflow ring 6outwardly of the same, defining the sealing cuff SC. The strip can befolded on its outflow end to provide a sealing collar along the valveperimeter, or a second strip can be connected by means of acircumferential stitching line to the first strip, to realize a sealingcircumferential collar.

The prosthetic leaflets 4 may be in any number compatible with operationas replacement heart valve. In some embodiments, the set includes a pairof leaflets. In some embodiments, such as that shown in the figures, theset includes three prosthetic valve leaflets 4 (e.g. for an aortic valveprosthesis). In some embodiments, the set may include four leaflets 4.

In embodiments, the leaflets 4 can be made of biological material suchas, for instance, bovine or porcine pericardium. In other embodiments,the leaflets 4 can be made of non-biological material such as anon-biological woven or nonwoven fabric that exhibits hemocompatibilityproperties. An example of this is disclosed, for instance in EPapplication no. EP 16745505.4.

Each valve leaflet 4 includes a fluidodynamically proximal edge 4P withan arched pattern, which extends from a base portion at the upperpattern SH and along two adjacent pleat formations PF, and afluidodynamically distal edge 4D which extends towards the centralorifice of the prosthesis 1 so as to be able to co-operate with thehomologous edges of the other valve leaflets 4.

The terms “fluidodynamically proximal” and “fluidodynamically distal” asused herein refer to the free flow direction of the blood through theprosthesis, a direction that is bottom up as viewed in the figures ofthe annexed plate of drawings.

During operation (heart cycle) the valve leaflets 4 experiencedeformation, divaricating and moving up towards the armature 2 so as toenable free flow of the blood through the prosthesis.

When the pressure gradient, and hence the direction of flow, of theblood through the prosthesis tends to be reversed, the valve leaflets 4then move into the position represented in FIG. 1A, in which theyprevent the back flow of the blood through the prosthesis.

The prosthetic valve including the valve leaflets 4 can be, for example,a glutaraldehyde fixed pericardium valve which has three cusps that opendistally to permit unidirectional blood flow.

The pattern of arched struts 8 includes proximal ends 10 connected tothe annular part 6, and distal ends 12 spaced axially from the proximalends 10 and arranged at an end of the armature 2 opposite the annularpart 6. In embodiments, the distal ends 12 coincide with distal ends ofthe armature 2, and in embodiments where the distal end of the armature2 coincides with a distal end of the prosthesis 1 as a whole, the distalends 12 coincide with a distal end of the prosthesis as well (this isthe case of at least some of the embodiments depicted in the figures).

Owing to this layout, in embodiments, the prosthesis 1 includes aninflow portion IF essentially corresponding to the annular part 6(whether or not covered by the sealing cuff SC), and an outflow portionOF corresponding essentially to the distal region of the armature, i.e.that where the distal ends 12 are arranged.

The armature 2 further includes a plurality of sets 14 of anchoringformations 16 configured to protrude radially outwardly of the annularpart 6, each set 14 being supported by at least one of the annular part6 and a corresponding arched strut 8, and a plurality of support posts18, each supported by adjacent arched struts 8, wherein the sets 14 ofanchoring formations 16 alternate with the support posts 18 around thelongitudinal axis X1. In embodiments the support posts 18 areadvantageously cantilevered to adjacent arched struts 8 and areconfigured as fixing locations for the prosthetic valve, specificallyfor the pleat formations PF at the commissural points of the valve. Inthis regard, the posts 18 are wrapped by adjacent side wings SWpreviously stitched together during assembly of the prosthetic valve.

Referring again to FIGS. 2-5 , in embodiments each arched strut 8extends from a first proximal end 10, to a distal end 12, then to asecond proximal end 10 in a valley-peak-valley sequence, wherein valleysare located at the proximal ends 10, and peaks are located at the distalends 12. In embodiments the pattern of arched struts includes threeadjacent and preferably identical arched struts 8 (such as in thefigures). With reference to FIG. 5 and FIG. 6 , in embodiments, thearched struts 8 extend within the boundaries of the inner and outersurfaces of the armature 2, so as to be substantially free of anyprotrusion relative to those surfaces. In other embodiments the archedstruts may have an offset from the inner and outer surfaces of thearmature 2, meaning by this they may either protrude radially inwardlyor radially outwardly of two cylinder surfaces tangent to the inner andouter surfaces of the armature 2 (in the view of FIG. 6 , this wouldcorrespond to a radially inward or a radially outward offset from thecircular perimeter of the lumen defined by the armature 2.

In embodiments, the arched struts are sized and dimensioned so as tohave a variable curvature between a proximal end 10 and a distal end 12,for example with the arched shape starting with a 45 degrees tangent atthe proximal end 10, and ending up with an 80 degrees tangent at thedistal end, the angle being measured relative to a direction parallel tothe axis X1

In some embodiments, the arched struts 8 are sized and dimensioned so asto exhibit appreciable variations in curvature between proximal anddistal ends 10, 12. The pattern of arched struts 8 includes distalportions 20 located at the distal ends 12, and inter-strut portions 22located at the proximal ends 10. The distal portions 20 may be shaped soas to provide a marked local variation in the shape of the strut, forexample by exhibiting a C-shape as shown in the figures. The distalportions 20 may provide coupling locations for other devices such as avalve holder or a hub of a carrier portion of a delivery catheter. Inother embodiments, the distal portions 20 may be provided as closed-loopstructures such as eyes or eyelets. Note also that closed loopstructures may be provided at the annular part 6 (either as part of thearmature 2 or on the sealing cuff SC, for example as loops made of yarnand weaved through the cuff SC) as coupling elements intended to beengaged e.g. by valve loading or crimping facilities or instruments.

In embodiments, the inter-strut portions 22 are essentially V-shaped andare defined by the roots of the adjacent arched struts departing fromthe same proximal end 10. In some embodiments, the inter strut portions22 may exhibit a Y-shape or a U-shape. An example of a Y-shape is shownin the figures (particularly FIGS. 2-5 ) wherein each inter-strutportion 22 extends through the mesh of the annular part 6. In theseembodiments, the mesh of the annular part 6 is provided as a sequence ofrhomboidal strut clusters (cells) sequentially connected to each otherat endpoints of a diagonal line (such as the shortest diagonal) andexhibiting accordingly an identical circular pattern of free ends onopposite sides of a circumference extending through the sequence of theconnection points. The Y-shaped inter-strut portion 22 is thusintegrally formed at a selected connection point between two adjacentrhomboidal strut clusters, and may extend no further than the proximalend of the armature 2.

In embodiments the strut clusters may be arranged according to an arrowshape, i.e. defined by two axially staggered sinusoidal patterns,circumferentially in phase, bridged by longitudinal struts.

In embodiments, the support posts 18 are angularly arranged at aninter-strut location, i.e., a circumferential location arranged at anarea where an inter-strut portion 22 (as well as accordingly a proximalend 10 shared by two adjacent arched struts 8) is provided. The supportposts may be provided as cantilevered to both the adjacent arched struts8 intervening at an inter-strut portion 22 via a first and a secondcantilever struts 24, 26, each connected to a corresponding one of saidadjacent arched struts 8 as shown in the figures. In some embodiments,each cantilever strut 24, 26 may be a twin strut.

The cantilever struts 24, 26 merge into each corresponding post 18starting from locations on respective arched strut 8 approximatelyhalfway through the portion of the arched strut 8 extending from aproximal end 10 to a distal end 12. Note that in other embodiments thesupport posts 18 may be cantilevered to the annular part 6, for exampleby being formed integrally with the inter-strut portion 22 (which inthis case will exhibit a trident shape).

The connection points at which the Y-shaped inter-strut portion 22 isformed may be chosen so that the same portions are evenly spaced(angular-wise) around the axis X1. The same applies to the support posts18, which may be arranged so as to be evenly spaced (angular-wise)around the axis X1.

In some embodiments shown in the figures, the armature 2 comprises threearched struts 8, three posts 18 spaced 120° around the axis X1, andthree sets 14, so that the sequence around the axis X1 is post 18-set14-post 18-set 14-post 18-set 14 (in this sense, even the struts 8 andthe sets 14 do follow a 120 degree-like distribution). In embodimentsthe three sets 14 include each a pair of anchoring formations 16,wherein each set 14 (and accordingly each anchoring formation 16)extends bridge-wise between the annular part 6 and the correspondingarched strut 8. In embodiments, each pair of anchoring formations 16extend bridge wise at an intra-strut location, that is a location withinan arched strut 8 and as such comprised between two proximal ends 10 ofthe same arched strut 8 and under a distal end 12/distal portion 20. Inother words, each set 14 of anchoring formations 16 extends bridge-wisefrom the arched strut 8 to a portion of the annular part 6 comprisedbetween two proximal ends 10.

The support posts 18, accordingly, are arranged at an inter-strutlocation (e.g. above the inter-strut portion 22 as shown in the figures)so that the sequence post 18-set 14-post 18-set 14-post 18-set 14 isprovided, location-wise, asinter-strut-intra-strut-inter-strut-intra-strut-inter-strut-intra-strut.

In embodiments, the support posts 18 are provided with bores 28configured for receiving sutures or stitches that fix the commissuralportions (pleat formations of the valvular sleeve) to the posts 18,hence fixing the prosthetic valve to the armature 2. In someembodiments, the prosthetic valve is fixed to the support posts 18 withthe same being completely outside of the valve. Sutures or stitches arerouted through the bores 28 and through the valve layers contacting thecorresponding post 18 from inside of the lumen. In other embodiments,the posts 18 may be wrapped by the valve layers—particularly by thecommissural points of the valve—so that the valve is at least partially“outside” of the posts 18.

In embodiments, the anchoring formations may include a serpentine orotherwise weaving portion between opposite ends thereof. Such aserpentine or otherwise weaving portion is intended to provide a largerfootprint to the anchoring formation at the interface with a ValsalvaSinus, and additionally it enables the bulging of the anchoringformations to a diameter larger than the inflow diameter, typically 1.4or 1.5 times the inflow diameter.

The prosthesis 1 shown in FIG. 1A is particularly suitable as aorticvalve prosthesis, i.e. for replacement of an aortic valve. To this end,the prosthetic valve includes three identical leaflets 4 and thearmature 2 is designed as a whole—as described above—according to120°—spacing (or, where appropriate, a ⅓ coverage) criteria: three posts18 at 120° apart, three sets 14 evenly distributed around the axis X1,and three arched struts 8 covering approximately one third of thecircumferential extension of the annular part 6.

The prosthesis 1 may be implanted as shown in FIG. 7 , so that theinflow portion IF at the annular part 6 occupies a proximal positionrelative to the Valsalva sinus VS, including a native valve annulus,while the anchoring formations 16 extend into the lobes of the Valsalvasinus VS (one set 14 per each Sinus) to firmly anchor the prosthesis 1in place. The pattern of arched struts 8 is configured to follow thecontour of the Valsalva Sinus at the interface with the ascending aorta,distally of the Sinus itself. The distal portions 20 of the distal ends12 in various embodiments are intended to sit just distally of theSinus.

In embodiments, achieving this placement of the prosthesis 1 may includesizing and dimensioning the prosthesis according to the followingspecifications (all endpoints included in the ranges):

axial length of the annular part 6 (inflow portion IF): 7 to 10 mm;

total axial length of the prosthesis (e.g. measured from a proximal endof the inflow portion If to the distal portions 20): 25 to 37 mm;

expanded diameter of the inflow portion IF (outer diameter of annularpart 6, including sealing collar SC: 23 to 33 mm; and

extended outer diameter of anchoring formations 16, measured at the mostradially outward portion of the anchoring formations: 31 to 44 mm.

Additionally, the prosthetic valve carried by the armature 2 may besized and dimensioned according to the following specifications:

ventricular protrusion: 5 to 8 mm; and

implantation diameter: 19 to 29 mm.

The paired anchoring formations 16—especially when provided with aserpentine or otherwise weaving pattern as shown in thefigures—favourably contact the Sinus to hold the prosthesis 1 in placeby bulging radially outwardly of the armature 2. The anchoringformations 16 of each pair may advantageously be positioned on oppositesides of the coronary ostia in the respective sinuses of Valsalva, withthe serpentine or otherwise generally weaving (or else aperture)structure thereof substantially avoiding interference with the coronaryostia.

The armature 2 of the prosthesis 1, according to embodiments, ismanufactured by first cutting a blank part from a tube of abiocompatible metal (e.g., Nitinol, or a cobaltum-chromium alloy) havingan outer diameter which is at an intermediate size between the fullyradially contracted and the fully expanded device dimensions. Forexample, the tube may have an outer diameter of between about 10 mm toabout 14 mm. In some embodiments, the tube has a diameter of about 12mm. In some embodiments, the tube wall may vary between about 0.4 mm toabout 0.6 mm, depending on the required stiffness required and the sizeof the prosthesis 1.

In embodiments, the final dimension and shape of the framework isachieved by a sequence of expansion cycles. A specific heat treatment isapplied after each expansion cycle to homogenize and stress relieve thematerial, which allows the shape and properties of the structure of thearmature 2 to be set. Although the number of forming steps may varyamong devices, for the geometries described above with respect to thepresent disclosure, and using Nitinol for the tube blank, an exemplarynumber of forming steps is around three. Among these steps, the firsttwo provide the final diameter of the annular part 6. For example, ifthe fully-expanded diameter for implantation is 20.5 mm, the finalcylindrical shape of the armature 2 can be achieved using a tube blankof about 12 mm in inner diameter, a first expansion from about 12 mm toabout 15 mm, and a second expansion from about 15 mm to about 19.5 and athird expansion from about 19.5 to 21.5 mm. Optionally, the finaldiameter can be made slightly larger (e.g. about 21.5 mm in the previousexample) in order to oversize the armature 2 with respect to thephysiological annulus, thus imparting a radial force to the wall of theannulus at the nominal implant diameter.

All the forming steps are also aimed to impart the radially-extendingshape of the anchoring formations 16 such that they will fit and anchorwithin the Valsalva sinuses.

After the forming process is complete, the armature 2 may undergo one ormore surface treatments, for example, sandblasting and electropolishing,to provide a sufficiently smooth surface and to remove the shallowdefects. The armature 2 may thereafter be finally exposed to a carboncoating process in order to improve its hemocompatibility.

The final geometrical shape of the armature 2 will thus generallyapproximate the physiological shape and dimension of the aortic root,such that the anchoring formations 16 generally conform to the walls ofthe respective Valsalva sinuses VS.

The prosthesis 1 is delivered to the implantation site in a radiallycontracted condition, for example crimped and loaded into a deliveryinstrument such as a catheter. The prosthesis may be implanted usingminimally invasive techniques or via conventional surgical techniquessuch as sternotomy or thoracotomy. Once on site, the prosthesis 1 isreleased from the catheter so to allow the annular part 6 to expand tothe radially expanded configuration and the anchoring formations 16 tosettle into the Valsalva Sinus.

In embodiments, the provision of support posts 18 that are cantileveredto the arched struts 8 decouples the deformation pattern of the proximalportion of the prosthesis 1—that is, the annular part 6—from thedeformation pattern of the distal portion of the same prosthesis—thatis, the portions of arched struts 8 converging to the distal ends 12. Ifthe implantation site has an irregular shape (like a D-shape) such as toresult in substantial alterations of leaflet functionality with priorart prostheses, the prosthesis 1 on the contrary allows the annular partto adapt to the shape of the implantation site without transmitting anyof the deformations resulting therefrom to the support posts 18, whichessentially maintain the advertised position on the armature 2 byremaining spaced 120 degrees apart. In the case of an aorticimplantation site, the deformation pattern of the annular part 6 may belargely variable on account of the shape of the site per se, and/or thesize of calcium deposits possibly present at the implantation site,while the deformation pattern of the arched struts 8 maybe—instead—reasonably predictable and regular on account of a lesservariability of conditions at the locations concerned (Valsalva Sinus andascending aorta). Therefore, the support posts 18 may take benefit fromhighly predictable and reasonably regular deformation of the portions ofthe armature it is attached to, thereby keeping the relative positionthereof and allowing the prosthetic valve with the valve leaflets 4 tooperate as efficiently as possible, and ultimately independently of theshape and conditions of the implantation site.

Additionally, folding phenomena of the prosthesis are avoided owing tothe armature design. Folding generally occurs on account of an inwardrotation of the anchoring formations 16, wherein one rotates clockwise,and the other one rotates counterclockwise to jointly result in aninward displacement of annular part 6. Anchoring formations 16 bridgingtwo structural portions having a substantial axial extension and/orresistance to bending (relative to that of the anchoring formations) mayencourage—undesirably—these pheonomena, as the anchoring formations endup with accommodating a major share of deformations within the armature2, which the structural portions above (e.g. two annular portions atopposite ends of the armature) inherently cannot accommodate.

Because the armature 2 features the pattern of arched struts 8, theanchoring formations 16 essentially bridge one structural portion, suchas the annular part 6, that has a substantial axial extension and/orresistance to bending relative to the formations 16, and anotherstructural portion such as the arched struts 8 which is subject to abinding structural constraint primarily at the proximal portions thereof(i.e. the proximal ends 10 and the inter-strut portions 22, while thedistal portions 20 at the distal ends 12 are relatively free toaccommodate deformations running through the armature from theproximal—stiffer-portions thereof (e.g. the inflow). This difference instrength or biding amount of the structural constraints the archedstruts 8 are subject to allows to divert away from the anchoringformations the structural actions that would otherwise tend to rotatethe anchoring formations 16. Diversion may occur, for example, over thelength of the arched struts and/or towards the distal ends 12 thereof.

In other words, the arched struts tend to compensate (essentially inthat they have a lesser degree of constraint to the remainder of thearmature) the torsional forces on the anchoring formations 16, therebykeeping the same separate from one another and the armature 2 as a wholeas close as possible to the intended shape.

Naturally, while the ideas and the principles of the disclosure remainsthe same, the details of construction and the embodiments may widelyvary with respect to what has been described and illustrated by way ofexample, without departing from the scope of the present disclosure.

Various modifications and additions can be made to the exemplaryembodiments discussed without departing from the scope of the presentdisclosure. For example, while the embodiments described above refer toparticular features, the scope of this disclosure also includesembodiments having different combinations of features and embodimentsthat do not include all of the described features. Accordingly, thescope of the present disclosure is intended to embrace all suchalternatives, modifications, and variations as fall within the scope ofthe claims, together with all equivalents thereof.

What is claimed:
 1. A method for implanting a cardiac valve prosthesis,the method comprising: advancing a cardiac valve prosthesis in acontracted state to an implantation site, the cardiac valve prosthesiscomprising an armature and a set of prosthetic valve leaflets supportedby the armature, the armature comprising an annular part, a plurality ofarched struts coupled to the annular part, a plurality of support postssupported by adjacent arched struts, and a plurality of sets ofanchoring formations; and deploying the cardiac valve prosthesis at theimplantation site such that the plurality of sets of anchoring formationprotrude radially outward of the annular part, each set supported by theannular part or a corresponding arched strut or both.
 2. The method ofclaim 1, wherein deploying the cardiac valve prosthesis comprisesdeploying the cardiac valve prosthesis at an aortic valve site.
 3. Themethod of claim 1, wherein deploying the cardiac valve prosthesiscomprises causing the plurality of sets of anchoring formations toprotrude radially outwardly of the annular part to contact a Valsalvasinus at the implantation site to anchor the cardiac valve prosthesis.4. The method of claim 1, wherein advancing the cardiac valve prosthesiscomprises advancing the cardiac valve prosthesis that has been crimpedand loaded into a delivery instrument, and wherein deploying the cardiacvalve prosthesis comprises releasing the cardiac valve prosthesis fromthe delivery instrument.
 5. The method of claim 4, further comprising,prior to the advancing, crimping and loading the cardiac valveprosthesis into the delivery instrument.
 6. The method of claim 1,wherein advancing the cardiac valve prosthesis comprises accessing theimplantation site using minimally invasive techniques.
 7. The method ofclaim 1, further comprising, after the deploying, permitting the set ofprosthetic valve leaflets to move, under the action of blood flow, to aradially divaricated condition to enable the flow of blood through alumen of the cardiac valve prosthesis in a first direction, and to aradially contracted condition, in which the set of prosthetic valveleaflets co-operate with one another and block the flow of blood throughthe cardiac valve prosthesis in a direction opposite the firstdirection.
 8. The method of claim 1, wherein each set of anchoringformations extends bridge-wise between the corresponding arched strutand the annular part.
 9. The method of claim 1, wherein the supportposts are cantilevered to adjacent arched struts.
 10. The method ofclaim 1, wherein the cardiac valve prosthesis is a replacement for anaortic valve.
 11. The method of claim 1, wherein each set of anchoringformations comprises a pair of anchoring formations.
 12. The method ofclaim 11, wherein deploying the cardiac valve prosthesis comprisespositioning each pair of anchoring formations on opposite sides of acoronary ostia in the respective sinuses of Valsalva, therebysubstantially avoiding interference with the coronary ostia.
 13. Themethod of claim 1, further comprising sealing the cardiac valveprosthesis at the implantation site via a cuff covering the annular partand arranged outside of a lumen of the armature.
 14. The method of claim13, wherein the cuff is separate from the set of prosthetic valveleaflets.
 15. The method of claim 1, wherein the annular part includesone or more coupling elements configured to be engaged by valve loadingor crimping facilities or instruments.
 16. The method of claim 1,wherein the sets of anchoring formations alternate with the supportposts around a longitudinal axis of the cardiac valve prosthesis. 17.The method of claim 1, wherein each anchoring formation comprises aserpentine, a weaving, or an apertured pattern.
 18. The method of claim1, wherein each support post is angularly arranged between two adjacentarched struts at an inter-strut position, the inter-strut positioncorresponding to the position of a proximal end shared between the twoadjacent arched struts.
 19. The method of claim 1, wherein each archedstrut includes a distal portion at a distal end thereof which issubstantially C-shaped and is configured to mate with a valve holder ora carrier portion of a delivery instrument.
 20. The method of claim 1,wherein the plurality of arched struts includes inter-strut portionsarranged at proximal ends, and the annular part has a mesh structureincluding cells and nodes, and wherein the inter strut portions have aY-shape or a U-shape extending through the cells or nodes of the meshstructure of the annular part.